Treatment Of Osteonecrosis Using BMSCs

Previous studies have provided evidence for the existence of bone marrow-derived mesenchymal stem cells(BMSCs).This bone marrow stromal stem cells population demonstrates extensive proliferation and retains the capacity for differentiation into bone,cartilage and adipose tissue in vitro.BMSCs are a major source of osteoblasts and are crucial for bone remolding and repair and thus they are widely used for tissue engineering applications.Tissue engineering in combination with gene therapy is considered as a promising approach in new bone regeneration.Nontraumatic osteonecrosis of femoral head(ONFH)continues to be a significant challenge to orthopedic surgeons.Early identification and surgical intervention for ONFH may help preserve the femoral head.Bone Morphogenetic Protein-2(BMP-2)could provide cellular activity,specifically proliferation,migration,differentiation,maturation and extracellular matrix production.BMP-2 might regulateo steoblast differentiation and osteoclast proliferation.BMP-2 might provide new thoughts on development of future orthopedic biomaterials.Although BMP-2 has received considerable attention as a bone regeneration inducer,a high dose of BMP-2 is typically required due to its short life-time under in vivo conditions.We have proposed a method to enhance the osteogenetic differentiation ability of BMP-2 in vitro that is based on recombinant adeno-associated virus(rAAV)-mediated and gene transfection.BMP-2 was used to repair ONFH,which can maintain the osteogenic phenotype of seed cells,and effectively secrete BMP-2,and effectively promote blood vessel regeneration and contribute to formation and revascularization of tissue engineered bone tissues.First,the biological characteristics of BMSCs from gene transfection was observed.In vitro animal tests using six white New Zealand rabbits showed that the BMP-2enhanced bone formation and osseointegration.The morphology of Wright stained MSCs was observed under inverted microscope.The gene expression levels of osteoblastic genes were analyzed using calcification and enzymatic alkaline phosphatase(ALP)activity assessed the BMP-2induced osteogenic differentiation of human BMSCs.BMSCs were transduced withadeno-associated virus(AAV)carrying BMP-2.We examined the effects of recombinant adeno-associated virus(rAAV)-mediated overexpression of BMP-2.The activation of BMP-2 was measured by Western blotting.Effects of BMP-2 on osteogenic differentiation of BMSCs were assessed by von Kossa staining,ALP staining and ALP activity.In vitro experiments histological staining confirmed that BMP-2 could promote bone formation andosteogenesis of BMSCs.Second,to explore the value of transplanting rAAV-BMP-2-BMSCs to treat osteonecrosis of the femoral head.BMP-2 was used to repair avascular necrosis of the femoral head,which can maintain the osteogenic phenotype of seed cells,and effectively secrete and BMP-2,and effectively promote blood vessel regeneration and contribute to formation and revascularization of tissue engineered bone tissues.To observe the therapeutic effect on the treatment of avascular necrosis of the femoral head by using BMSCs modified by BMP-2 in vitro.The models were avascular necrosis of femoral head of rabbits on right leg.There groups were single core decompression group,core decompression and BMSCs group,core decompression and BMP-2 transfect BMSCs group.Necrotic bone was cleared out under arthroscope.Arthroscopic observation demonstrated that necrotic bone was cleared out in each group,and fresh blood flowed out.Histomorphology determination showed that blood vessel number and new bone area in the repair region were significantly greater at various time points following transplantation in the core decompression and BMP-2 transfect BMSCs group compared with single core decompression group and core decompression and BMSCs group.These suggested that BMP-2 gene transfection strengthened osteogenic effects of BMSCs,elevated number and quality of new bones and accelerated the repair of osteonecrosis of the femoral head.Again,treatment of early-stage ONFH with autologous implantationof iliac crest bone marrow-derived mononuclear cells,which contain tens of thousands of BMSCs,recently achieved a promising outcome.According to the ARCO stage,104 cases of early-stageONFH were recruited and randomly assigned to BMSCs treatment or core decompression treatment.Each BMSCstreated hip received femoral headimplantation of 1×106 autologous subtrochantericbone marrow-derived and ex vivo expanded BMSCs.The Harris hip score(HHS),and the volume of the necrotic lesion or the low signal intensity zone inthe femoral head were assessed before and 6,12,24 and 60 months after the initial operation.After average 60 months HHS follow-up and magnetic resonance imaging,B group of femoral head necrosis volume from 29.8%to 10.18%,preoperative Harris score 55.8 to 91.3 of postoperative,clinical success rate of 92.4%.Ex vivo expansion of autologous BMMSCs can reliably provide a greater number of BMSCs for ONFH implantation.This intervention is safe and effective in delaying or avoiding ONFH collapse,which may necessitatetotal hip replacement.Finally,the objective of this study was to explore the therapeutic effect of coredecompression and BMSCs on different venous stasis changes associated with ONFH.32 cases(32 hips)withcore decompression and BMSCs were retrospectively reviewed.The patients were evaluated preoperative X-ray and MR:according to the ARCO stage.Preo-perative MRI evaluation:(1)signal strength staging in femoral head;(2)marrow edema and joint effusion scores for joint stasis index.All patients were assessed with X-rayand MRI.The resultsin the middle of the treatment were poor results.The difference was statistically significant.Our results on radiographs and MRI provided a predictive prognosis for patients with ONFH at vein stasis.These suggested that BMP-2 gene transfection strengthened osteogenic effects of BMSCs,elevated number and quality of new bones and accelerated the repair of osteonecrosis of the femoral head.Ex vivo expansion of autologous BMMSCs can reliably provide a greater number of BMSCs for ONFH implantation.This intervention is safe and effective in delaying or avoiding ONFH collapse,which may necessitatetotal hip replacement.